This is a JSONPath implementation for PHP based on Stefan Goessner's JSONPath script.
JSONPath is an XPath-like expression language for filtering, flattening and extracting data.
I believe that is improves on the original script (which was last updated in 2007) by doing a few things:
- Object-oriented code (should be easier to manage or extend in future)
- Expressions are parsed into tokens using some code cribbed from Doctrine Lexer and cached
- There is no
eval()
in use - Performance is pretty much the same
- Any combination of objects/arrays/ArrayAccess-objects can be used as the data input which is great if you're de-serializing JSON in to objects or if you want to process your own data structures.
JSONPath | Result |
---|---|
$.store.books[\*].author |
the authors of all books in the store |
$..author |
all authors |
$.store..price |
the price of everything in the store. |
$..books[2] |
the third book |
$..books[(@.length-1)] |
the last book in order. |
$..books[0,1] |
the first two books |
$..books[:2] |
the first two books |
$..books[?(@.isbn)] |
filter all books with isbn number |
$..books[?(@.price<10)] |
filter all books cheapier than 10 |
$..* |
all elements in the data (recursively extracted) |
Symbol | Description |
---|---|
$ |
The root object/element (not strictly necessary) |
@ |
The current object/element |
. or [] |
Child operator |
.. |
Recursive descent |
* |
Wildcard. All child elements regardless their index. |
[,] |
Array indices as a set |
[start:end:step] |
Array slice operator borrowed from ES4/Python. |
?() |
Filters a result set by a script expression |
() |
Uses the result of a script expression as the index |
$data = ['people' => [['name' => 'Joe'], ['name' => 'Jane'], ['name' => 'John']]];
$result = (new JSONPath($data))->find('$.people.*.name'); // returns new JSONPath
// $result[0] === 'Joe'
// $result[1] === 'Jane'
// $result[2] === 'John'
The options flag JSONPath::ALLOW_MAGIC
will instruct JSONPath when retrieving a value to first check if an object
has a magic __get()
method and will call this method if available. This feature is iffy and
not very predictable as:
- wildcard and recursive features will only look at public properties and can't smell which properties are magically accessible
- there is no
property_exists
check for magic methods so an object with a magic__get()
will always returntrue
when checking if the property exists - any errors thrown or unpredictable behaviour caused by fetching via
__get()
is your own problem to deal with
$jsonPath = new JSONPath($myObject, JSONPath::ALLOW_MAGIC);
For more examples, check the JSONPathTest.php tests file.
Script expressions are not supported as the original author intended because:
- This would only be achievable through
eval
(boo). - Using the script engine from different languages defeats the purpose of having a single expression evaluate the same way in different languages which seems like a bit of a flaw if you're creating an abstract expression syntax.
So here are the types of query expressions that are supported:
[?(@._KEY_ _OPERATOR_ _VALUE_)] // <, >, !=, and ==
Eg.
[?(@.title == "A string")] //
[?(@.title = "A string")]
// A single equals is not an assignment but the SQL-style of '=='
JMESPath does similiar things, is full of features and has a PHP implementation
The Hash utility from CakePHP does some similar things
The original JsonPath implementations is available at http://code.google.com/p/jsonpath and re-hosted for composer here Peekmo/JsonPath.
ObjectPath (https://github.com/adriank/ObjectPath) appears to be a Python/JS implementation with a new name and extra features.
- Added JSONPathToken class as value object
- Lexer clean up and refactor
- Updated the lexing and filtering of the recursive token ("..") to allow for a combination of recursion and filters, eg. $..[?(@.type == 'suburb')].name
- Various bug fixes and clean up
- Added a heap of array access features for more creative iterating and chaining possibilities
- Init